Comparison of effects of gastric bypass and biliopancreatic diversion with duodenal switch on weight loss and body composition 1-2 years after surgery.

BACKGROUND: Gastric bypass (GB) is the most common surgical procedure for weight loss in the United States. Biliopancreatic diversion with duodenal switch (BPD/DS) is less routinely performed, perhaps because of its technical difficulty and metabolic concerns. The objective of this study was to determine whether these procedures had differential effects on weight loss and body composition. METHODS: Body composition was measured by bioimpedance (Tanita 310) at the initial consultation, and follow-up measurements were completed 1-2 years after surgery. RESULTS: Of the 72 patients in the study, 50, aged 46.2 +/- 8.5 years, had undergone GB and were measured 15.5 +/- 5.2 months after surgery and 22, aged 40.6 +/- 7.9 years, had undergone BPD/DS and were measured 19.5 +/- 7.5 months after surgery. Patient age and time after surgery were significantly different between the 2 groups. The body mass index (BMI) for the BPD/DS group was 53.6 +/- 11.9 kg/m(2), significantly greater than the BMI of the GB group (48.0 +/- 6.3 kg/m(2); P = .009). However, the percentage of body fat did not differ between the 2 groups (P = .515). Postoperatively, the BMIs for the GB group (31.5 +/- 5.0 kg/m(2)) and BPD/DS group (30.3 +/- 6.1 kg/m(2)) were not significantly different (P = .384). The percentage of body fat for the GB and BPD/DS groups had changed from 49.2% +/- 8.3% to 32.1% +/- 10.6% and 47.9% +/- 5.9% to 23.8% +/- 10.4%, respectively (P = .002). The BMI had decreased by 16.5 +/- 4.8 kg/m(2)after GB and 23.3 +/- 6.8 kg/m(2) after BPD/DS (P <.001). The decrease in fat was 17.1% +/- 8.2% after GB and 24.2% +/- 7.2% after BPD/DS (P <.001). CONCLUSION: The BPD/DS procedure is more effective in reducing the BMI and promoting fat loss than is GB. The assessment of the impact of these two operations on an individualized basis offers additional information to assist in the evaluation of these procedures.